Maxine not shifting out

[CptTrog]

Hello again, everyone. Haven't been around for a bit. Been enjoying having mom's Burb not acting up. Until this week. Sitting in the drive next to her one cold and rainy morn as she tried to start up and watched a starter bolt break off and fall out. Nice.
Got it drilled out and replaced. Still gotta get the front bracket mounted back. (Need to find an octopus that can handle the tools!) Also need to determine what a small diameter green wire that's hanging down near the starter oughta be connected to! Looks like it was broken off recently. Comes down alongside the loom housing the larger purple wire to the starter but in its own small loom.

Remounted the starter. Test started fine, but first trip out of the driveway reveals she won't shift out of first.:mad2: Fluid level is fine.
Looked over the threads here and found one on a `92 that talks about the VSS and two solenoids/sensors. Any more feedback on this would be great. For instance, where are these located? If they're really that cheap, it may just pay to replace both.
(BTW, been waiting three weeks now for the Stealer here to deliver the new turbo hose clamp and new electrical connector for the boost sensor. :mad5: )

Thanks!

 

[Matt Bachand]

Small green wire sounds like a glowplug wire... check out the pass bank glow plugs for the one missing the wire!

 

[bk95td]

Check grounds at rear of intake manifold.Large[12 gauge] black is tranny ground. Check fuses. Tranny probly isn't getting power.

 

[buddy]

Either a ground to the tranny or the signals to and from the VSSB arent getting to the PCM. Such as the VSS. The PCM shifts off of a Throttle position and MPH.

The VSS should be a lt grn/blk wire. So if it green and black thats what it is. It goes into the dash to the VSSB module right behind your glove box. Pin C7. There is a blk/wht wire that is the ground for the VSSB that will be on the intake plenum on passenger side like bk95td was saying. That ground also goes to the OBD1 DLC port under the dash, pin A. So if you check continuity between chassis and pin A and get more than an ohm then you know that ground is no good.

The other VSS wire is ppl/wht, so if thats in the loom too you know its that.

 

[CptTrog]

I think the hanging green is a glow plug. Haven't been able to trace it to a specific plug; can't reach them under the turbo and exhaust manifold.
The VSSB ground at the intake is intact, as are two others grounded to the mount studs.
Funny thing is, once I got the starter mounted back on, the tranny began working like a champ.
About all I can do at this point is start looking for loose wires in all the places mentioned above.
As always fellas, thanks again!

 

[kevin265]

I bet its the wire for the GPR! Connect it to the starter solenoid. It cut's the power to the GPR when you turn the key to start. (No glowplug wire could reach the stater!)

 

[CptTrog]

Thanks, Kevin. The wire ended up being a glowplug wire after all. And the tranny's still working as designed. For now...
Fingers crossed!!

 

[NVW]

I bet its the wire for the GPR! Connect it to the starter solenoid. It cut's the power to the GPR when you turn the key to start. (No glowplug wire could reach the stater!)

First post and it's a winner:thumbsup: Welcome to the site

 

[buddy]

I bet its the wire for the GPR! Connect it to the starter solenoid. It cut's the power to the GPR when you turn the key to start. (No glowplug wire could reach the stater!)

There is not actually a wire from the starter to the GP controller in any OBD1 trucks. It has a power source to it only on when the ignition is in the on/run position, and not the crank/start position. And it will only glow when the PCM sends 12V to it as well, so two voltage inputs required to make glow.

Its possible that the wire that goes back to the controller from the passenger side glows is that long if it breaks, doesnt have to be the plug end dangling.

In the older pre-PCM 6.5s there is a wire that goes to the GP controller that is hot when the ign is in crank/start position, however I dont think that is to shut off the glows. And it just comes from the fuse panel off of the ignition switch, not all the way from the starter. That "hot in crank" line also goes to the LP relay, so the LP is running during crank, and the LP runs during glow too because its powered when the GP controller is running. The power comes back to the GP controller harness from the GP output itself. The Glow time in the pre-PCM 6.5s is dependent on the temperature of the GP controller itself, meaning engine bay radiant heat determines glow time.

Does glow actually stop in a 92 or 93 when you start cranking?

 

[kevin265]

I'm sorry, the color of the wire is Purple. Yes, it goes from the starter solenoid to the GPR. I was making an assumption as to its function because it made sense. My experience with 6.5s is I own a fleet of buses in Mexico. All of my buses are 95 Chevrolet G30s. All have 6.5 non turbo engines. When I searched for wiring diagrams for the engines the only thing that would match up was 1989 6.2 diagrams. If someone can explain that one I'm open.

 

[kevin265]

Well so much for my theory. I just went out and kicked the starter with the GPR light on and it did not interupt the light. 1000 sorrys for posting bad info. It won't happen again.

 

[buddy]

No problem, but you are mostly correct, there is a purple and white wire which does go to the GP controller/relay in Pre-PCM trucks. That wire goes to a hot when cranking circuit. However its hot when cranking not from the starter, but from the ignition switch in the start position. And what it does is power the LP relay coil during Wait To Start for the GPs.

In 94-95 they removed that functionality from the GP controller to LP relay, so we dont have LP priming during WTS like in 92-93. 96+ OBDIIs have this functionality because the LP relay coil is excited by the PCM directly during WTS, crank and operation.

And the busses and vans always kind of lagged the updates of the pickups, mostly because they sold less and they didnt necessarily have the emissions restrictions.

 

[CptTrog]

After nearly pulling all my hair out and almost spending a pant load of money on a tranny job, I more or less stumbled on a fair cheaper solution:
THE ALTERNATOR!!!! Believe it or not, a new alternator has fixed far more than just a low voltage indication on the dash. The tranny is shifting out smoother than I could have imagined!